Comments on: How Fast is the Universe Expanding?https://www.universetoday.com/118785/how-fast-is-the-universe-expanding/
Space and astronomy newsMon, 19 Mar 2018 13:39:24 +0000hourly1https://wordpress.org/?v=4.9.4By: Peter Wilsonhttps://www.universetoday.com/118785/how-fast-is-the-universe-expanding/#comment-145969
Tue, 10 Feb 2015 15:26:11 +0000http://www.universetoday.com/?p=118785#comment-145969How fast is the universe expanding?
Picture 100 Mly of space the size of a beach-ball. Wait a million years. Expanding at the Hubble rate of 68 km/s per megaparsec, the beach-ball will have expanded by 1/10th of a mm, about the thickness of plastic wrap.

For comparison, the Moon’s orbit is expanding at the rate of 100 km/s per megaparsec. That sounds fast, but we wouldn’t know that without the most precise measurement’s of its distance imaginable. The expansion of the cosmos is glacial. As with the cosmos, the expansion of the Moon’s orbit is accelerating.

]]>By: Sean Nelsonhttps://www.universetoday.com/118785/how-fast-is-the-universe-expanding/#comment-145946
Tue, 10 Feb 2015 03:10:20 +0000http://www.universetoday.com/?p=118785#comment-145946” Why is space expansion occurring only far out but not locally?”
Actually the author here didn’t say that he said ” space is expanding everywhere in all places”
]]>By: john kulickhttps://www.universetoday.com/118785/how-fast-is-the-universe-expanding/#comment-145939
Mon, 09 Feb 2015 20:10:18 +0000http://www.universetoday.com/?p=118785#comment-145939According to the “mainstream” description of the expansion, the expansion of spacetime stops at the boundary of gravitationally bound galaxies. Atoms are even more tightly bound so they would be even more resistant to expanding.
A common example you would see in an astronomy book describing the expansion is that of buttons glued on to an expanding balloon; the buttons represent the fixed sized galaxies and the expanding surface represents a dimensionally reduced example of the expansion of spacetime.
If the expansion of spacetime included matter, or was a continuous feature assocated with space, even the space within the atom, it would take about 14 x 10^9 years for a meter stick to double in size. This, for the most part, would be very difficult to measure.
(I have developed a fairly convincing model which allows the expansion of spacetime to include the space within the atom, but that is not what you were asking about, but it is the reason I am familiar with the “standard ” model.)
]]>By: Tom2morohttps://www.universetoday.com/118785/how-fast-is-the-universe-expanding/#comment-145938
Mon, 09 Feb 2015 19:11:14 +0000http://www.universetoday.com/?p=118785#comment-145938I appreciate your explanation, which confirms what I have read before about space expanding, but you did not explain what I have not been able to learn as yet: Why is space expansion occurring only far out but not locally?
Is it not noticeable at our local rate, or what?
]]>By: dimarhttps://www.universetoday.com/118785/how-fast-is-the-universe-expanding/#comment-145937
Mon, 09 Feb 2015 18:58:48 +0000http://www.universetoday.com/?p=118785#comment-145937I wonder how would we perceive the universe if we/humans were smaller than an atom? Would everything be totally different?
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